Process and apparatus for making sausage casings and the like



Nov. 2, 1937. R. 1 ATKlNsoN PROCESS AND APPARATUS FOR MAKING SAUSAGE CASINGS AND THE LIKE Filed May 1., 1933 2 Sheets-Sheet 1 Nov. 2, 1937.

R. l.. ATKINSON 2,097,684

PROCESS AND APPARATUS FOR MAKING SAUSAGE CASINGS AND THE LIKE Filed May 1, 1935 2 Sheets-Sheet 2 PatentedNovlIZ, 1937 n n `4 y UNITED STATES PATENT OFFICE PROCESS AND APPARATUS FOR MAKING SAUSAGE CASINGS AND THE LIKE Ralph L. Atkinson, Boston, Mass.

Application VMay 1, 1933, Serial No. 668,712 Renewed August 4, 1934 4 Claims. (Cl. 18-15) My invention relates to improvements in the main body or casing I0, shown as an annular art of making tubing of cellulose hydrate for casting or sleeve, having a cover II bolted to the sausage casings and the like. Heretofore such upper end thereof and a conical annular die tubing has been formed of cellulose hydrate, by member I2 bolted to the bottom thereof. Save 5 dissolving cellulose by the well known viscose for the annular die opening 23 through which 5 process, to form a viscous solution, and extruding the cellulose solution is extruded, the lower end the solution continuously through'an annular die, of the body and the chamber thereof are closed thus forming it into a thin-walledatubing and by an internal die member or mandrel I3. The thereafter coagulating or precipitating the cellubody of the mandrel I3 is tapered on its outer lose hydrate of the tubing by applying thereto a periphery to substantially correspond to the taper 10 suitable coagulant or hardening agent. A procof `the inside of the wall of the die I2 and is ess and apparatus for this purpose are disclosed spaced from the latter, with which it is coaxial, in United States Patent No. 1,163,740, granted to a suitable distance to provide an annular passage Cohoe December 14, 1915. My invention probetween the two of the proper size to form a vides certain improvements in process and aptubular film of the thickness required to produce l5 paratus of this character, whereby a more unia tubing of the desired wall thickness. In the form and satisfactory'product may be continu-V specific structure shown, the mandrel I3 is ously, uninterruptedly and rapidly produced with formed with a conical upper end and is supa minimum of attention and manipulation upon ported from the cover I0 by a sleeve I4 threaded the part of the operator. into the mandrel atV I5 and into an opening in 20 The preparation of the viscose solution, as it the cover at I6. The sleeve is formed with an is used in my process and apparatus,'is well annular ange I1 the upper surface of which is known and need not be here described, savethat shaped to conform to the bell shape of the upper it is desirable to use a solution of relatively high surface of the mandrel. Obviously, by turning viscosity of the nature of a plastic as thereby the the sleeve I4 it may be adjusted vertically 25 tubing as it isV produced is of greater strength through the cover II to adjust the thickness of and tenacity during the period before it has beenV Iilm produced between the die I2 and the mancompletely coagulated and hardened. I may emdrel. The mandrel may be accurately centered ploy any ofthe well known coagulants, commonly in the die by means of the adjusting screws I8 employed for precipitating viscosefrom solution, threaded through the walls of the casting I0 and 30 but preferably employ an acid reagent for this eng-aging the sleeve I4. purpose, dissolved in water in the usual concen- The viscose solution is supplied to the chamber tration. I9 of the forming head through a pipe 20 con- `lVIy invention relates to the Aprocess and appaneed With a Suitable Supply Vessel G0 be 16- ratus for extrudingnand coagulating the' tubing. ferred to later, containing a body of the solution. 35

In the drawings accompanying and forming a A bell-shaped skirt or extension 2| is formed part of this specification, Figure 1 Shows my im.. on orsecured to the mandrel I3, the lower portion proved apparatus in vertical longitudinal section, 0f the Skirt being rounded 2S at 22 and 0f Someparts being shown in elevation, and what larger diameter than the die opening 23. Fig. 2 is a vertical section, partly in elevation, A T Coupling 24 iS SCIeWed G0 the upper' end 40 of the tube-forming head or extruding device. 0f the SleeVe I4, the OPDOSG branch 0f the T Y The apparatus shown in Fig. 1 comprises a being closed by a plug 25 The third Opening 0f precipitating -ltank 3, a washing or finishing tank thel T receives a pipe 23 thIOilgh Which a' Supply 4, a supply tank 5' for the coagulant orl precipiof coagulant or precipitating agent is received tating agent and an overflow tank 6. The formas Will be presently described- An exhaust pipe 45 ing head 'I is suitablysupported in tank 3 with 21 extends through the plus 25 to e suitable diS- itsannular die or forming' opening directed tance below the skirt 2| of the mandrel and also downwardly, and suitable guides, to be presently passes ,through a horizontal diaphragm 28 which described, are located within and above the tank cuts off communication between the upper and forA the purpose of receiving the tubing 9 as it lower portions of the bell-shaped skirt. The skirt 50 is formed and guiding it through theooaguiant sprovided above and below the diaphragm with bath within the tank by which the tube is hardannular series of openings 29, 3B for a purpose cned and set.` Y Y which will now be described. 1,- Referring now moreparticularlytp Fig; 2, it When the apparatus is in operation, the formwillbe seen that the forming head comprises a ing head receives a constant supply of cellulose 55 solution which is pumped through the pipe 28 from a suitable source, the solution lling the chamber and being forced or extruded through the annular opening between the die and Inandrel, and as the formed tube emerges it travels over the convex surface of the lower end of the bell and is somewhat stretched thereby. The forming head of the lower end thereof dips into the bath of coagulant or precipitating agent within the tank 3 and therefore as the tube emerges it is at once subject to the hardening effect of the coagulant by which it is surrounded. At the same time, coagulant is constantly supplied through the pipe 26 and the sleeve lll to the interior of the mandrel and the upper portion of the bell-shaped skirt 2l. The upper end of the skirt is reduced exteriorly at 3l so that an annular chamber is formed between the same `and the surrounding tubing 32 and the openings 29 above mentioned are so located as to communicate with the upper end of this chamber adjacent the die orV extrusionvopening. A'lo'wer annular series of openings 38 likewise Vcommunicate with this chamber, at its lower end, and the coagulant supplied to the interior of the mandrel and bell flows through the upper openings, washes and hardensV the inner surface of the tubing and ows from the lower end of the chamber into the interior of the lower portion of the skirt or bell. The coagulant is thus supplied also to the interior of vthe formed tubing between the bell and the first guide 8 under suflicient head to maintain the tubing distended against the pressure of the body of coagulant in tank 3. Further, enough of the coagulant escapes pastthe guide 8 to distend the tubing beyond said guide, as will be explained later. From the interior of the tubing an amount of coagulant escapes through the outlet pipe 2l to balance the inflow after normal conditions have been established.

As the' tubing is 'quite tender when freshly formed and therefore readily stretched or deformed until the cellulose is coagulated or hardened,'it' is" important that the interior pressure of the coagulant be nicely adjusted to substantially equal, or, preferably, slightly overbalance the external pressure of the body of coagulant in tank 3'in which the'tubing is submerged, so that the tubing may be properly distended but not unduly or irregularly stretched. For this purpose the level of the coagulant in supply tank 5 from which the coagulant flows through the tube 26 VVto the'interior of the tubing is carefully adjusted to and maintained at a height slightly abovethe height or level of the liquid in tank 3. A suitable means for this purpose is shown in the pvoted adjustable overflow pipe 35 in the supply tank which communicates with pipe 35 discharging into the overflow tank. The level of the coagulent in tank 3 is maintained constant by an overflow pipe" 36 likewise discharging into the overflow tank 6. From the latter, the coagulant is returned "in suflicient volume to maintain the level in the supply tank by a return pipe 31 and pump 38.'

As heretofore stated, the tubing as it is formed passes lthroughthe coagulant in tank 3 and is carried iirst around the guide 8, which may be an idle roll, and then upwardly through the bath to a pair of rolls 39 between which it passes, the rolls being so adjusted relative to each other as to properly flatten the tubing between them without' exerting undue pressure thereon. The tubing passes around roll 8 Vsuliiciently freely to permitan amount of coagulant to pass through v pregnation with glycerine.

the tubing about the roll and into the upwardly moving tubing between the guide roll 8 and the rolls 39 to hold the same partially distended against the pressure of the body of coagulant in the tank, tending to collapse it.

From the flattening rolls 39, the tubing passes back and forth around guide rods 48, 4l located above the level of the coagulant and guide rods 42 suitably located within the tank 3 and toward the bottom thereof until the material of the tubing is completely or sufficiently coagulated. From the last guide rod 42, the tubing passes over guide rods 43, 44 into the washing or other treating tank l where it is caused to travel similarly up and down through the tank about guide rods 55, 46.

In the practice of my process of making cellulose hydrate tubing, I prefer to use a viscose solution of relatively high viscosity and have successfully employed solutions of viscosities ranging from 250 to 450 seconds according to the oflicial method of the American Society for Testing Material as given in A. S. T. M. Tentative Standards, 1931, p. 358, Consistency, the material being tested at 18 C. I have found that most satisfactory results are obtained toward the upper limit of this range: of viscosity. Preferably the pressure of the internal body of coagulant below the forming head is so regulated as to distend or stretch the tubing laterally so that it exerts little, if any, pressure upon the bell 22 and it may even to advantage be stretched by the innercoagulant pressure to a diameter slightly in excess of that of the bell. The pressure of the internal body of coagulant below the Vbell is such as to prevent'any substantial contraction of the tubing as it travels from the bell to the reversing roller 8. Indeed, I have found that the bell may be omitted altogether and by properly regulating the pressure of the internal body, of coagulant the desired lateral or circumferential stretching may be satisfactorily accomplished.

It is to be understood that a drawing or tension mechanism, which may be of usual or known character, such as constantly driven rolls or a reel, is employed to take up or draw the tubing from the forming head and through the several baths to which it vis subjected, the tubing being taken up at a rate at which it is substantially stretched or drawn. I have successfully employed a take-up rate three or four times as great as the rate at which thev tubing is formed by the forming head. 'Ihe distension of the tubing by the internal pressure, together with the longitudinal tension to which it is subjected, serves to flatten the tube so that it passes smoothly and without wrinkles around the roll 8, and at the same time the tension is not suiiicient to prevent an amount of internal coagulant to pass the roller and distend the upwardly moving length of tubing between said roller and a pair of rolls 39.

From 'the rolls 39 the tubing passes back and forth through the coagulating bath as heretofore described and then through a further bath or baths for further treatment. This further treatment may include such well-known steps as subjecting the material to an additional bath of relatively weak acid coagulant, washing and im- After the treatment is completed the tubing may be wound up or subjected to a suitable drying operation immediately.

I claim:

1. In a forming head of the class described, a main body for receivingvr the material from which Cil tubing is to be formed by extrusion, said body having an exterior die member, a mandrel concentric and cooperating with the die member to form an annular die. opening therewith, a skirt on said mandrel having a lower portion of enlarged diameter as compared to the die opening, a sleeve supporting said mandrel and communicating with the interior thereof, means for supplying the sleeve with coagulant, the skirt of the mandrel being formed with upper and lower passages permitting the circulation of coagulant from the interior of the skirt through the latter and into a chamber formed between the skirt and the newly formed tubing, said skirt also being formed with lower openings permitting the coagulant to escape from said chamber to the interior of the skirt.

2. A process of forming tubing of cellulosic material for sausage casings or the like having a predetermined diameter comprising extruding downwardly in tubular form a plastic solution of cellulose and directly submerging the same in a coagulant bath, leading the tubing rst downwardly and then upwardly in the bath, continuously supplying coagulant to the interior of the downwardly and upwardly moving and submerged tube portions, determining the diameter of the tubing by establishing the pressure of the coagulant within the tubing in excess of that exerted by the bath, maintaining a sucient volume of coagulant within the tubing to hold the predetermined diameter, and evacuating the excess coagulant from the interior of the tubing.

3. A process of forming tubing of cellulosic material for sausage casings or the like having a predetermined diameter comprising extruding downwardly in tubular form a plastic solution of cellulose and directly submerging the same in a coagulant bath, leading the tubing first downwardly and then upwardly in the bath, continuously supplying coagulant to the interior of the downwardly and upwardly moving and submerged tube portions, determining the diameter of the tubing by establishing the pressure of the coagulant within the tubing in excess of that exerted by the bath, maintaining a sucient volume of coagulant within the tubing to hold the predetermined diameter, evacuating the excess coagulant from the interior of the tubing, collapsing the upper end of the upward tube portion within the bath, continuously removing the tubing from the bath and thereafter feeding the collapsed tubing through a second coagulant bath.

4. Apparatus for forming tubing of cellulosic material for sausage casings or the like having a predetermined diameter comprising a forming head having a tubular die, abath of coagulant into which the die opens downwardly, the delivery end of the die being submerged in the bath, a lower guide member within the bath and below the forming head about which the tubing is led, an upper guiding member to and about which the tubing is led from the lower guide member, and means for supplying coagulant to the interior of the tubing portions between the lower guide member and the forming head and upper guiding member, respectively, at a pressure in excess of that exerted by the bath and in sufcient volume to hold the predetermined diameter.

RALPH L. ATKINSON. 

